Voice-Sensitive Regions in the Dog and Human Brain Are Revealed by Comparative fMRI

Abstract

During the approximately 18-32 thousand years of domestication, dogs and humans have shared a similar social environment. Dog and human vocalizations are thus familiar and relevant to both species, although they belong to evolutionarily distant taxa, as their lineages split approximately 90-100 million years ago. In this first comparative neuroimaging study of a nonprimate and a primate species, we made use of this special combination of shared environment and evolutionary distance. We presented dogs and humans with the same set of vocal and nonvocal stimuli to search for functionally analogous voice-sensitive cortical regions. We demonstrate that voice areas exist in dogs and that they show a similar pattern to anterior temporal voice areas in humans. Our findings also reveal that sensitivity to vocal emotional valence cues engages similarly located nonprimary auditory regions in dogs and humans. Although parallel evolution cannot be excluded, our findings suggest that voice areas may have a more ancient evolutionary origin than previously known.

Lateralized Functions in the Dog Brain

“…Results revealed that dogs consistently turned their head to the right during presentation of human spoken commands with artificially increased segmental cues (i.e., higher salience of meaningful phonemic components); moreover, a significant left-turning bias was observed in response to manipulated commands with increased supra-segmental vocal cues (i.e., higher salience of intonation component). These results have been confirmed by recent neuroimaging studies and overall suggest a convergent lateralized brain specialisation between canine and human species for processing speech [9].…”

“…The complementary specialisation of dogs' brain hemispheres is clearly apparent at different sensory levels, including vision [5], hearing [6][7][8][9][10] and what is considered to be the most relevant sensory domain for canine species, namely olfaction [11,12].…”

“…There is now evidence that the auditory sensory system in the dog brain also works in an asymmetrical way depending on the type of acoustic stimulus [6,8,9]. Specifically, during feeding behaviour, dogs' head orienting responses to different sounds played at the same time from two speakers placed symmetrically with respect to the subjects' head were recorded [6] (see Figure 1A).…”

The Biology and Evolution of Speech: A Comparative Analysis

“…Regarding voice-specific processing, we have solid data only for primates, but again, voice-selective regions exist, suggesting that such regions constitute a primate synapomorphy at least. One recent study on dogs suggests that the existence of voice-selective regions may extend more broadly among mammals (Andics et al 2014).…”

Using music to study the evolution of cognitive mechanisms relevant to language

“…) Another option for neural studies is fMRI. This technique has recently been used to study voice-sensitive cortical regions in awake, unanesthetized dogs trained to lie still in an MRI scanner (Andics, Gácsi, Faragó, Kis, & Miklósi, 2014). Using the canine auditory fMRI method pioneered by Andics et al, one could determine if dogs, like humans, show increased activity in inferior frontal brain regions when hearing music that is harmonically complex versus simple, which would suggest cognitive processing of harmonic structure (cf.…”